The pozzolanic properties of a coal combustion bottom ash were investigated
. Plain pastes containing equal amounts of calcium hydroxide and bottom ash
were prepared and analyzed at different ages for their strength and the ca
lcium hydroxide consumption. At early ages, bottom ash does not react with
calcium hydroxide. Its pozzolanic reaction proceeds slowly and accelerates
gradually to become very interesting after 28 days and especially after 90
days. The strength activity indexes measured on mortars are sufficiently im
portant to allow the use of bottom ash in concrete. When ground for 6 h in
a laboratory ball mill, the 28-day strength activity index of bottom ash is
increased by 27%. (C) 1999 Elsevier Science Ltd. All rights reserved.